This invention relates to compositions comprising hydroxy-functional polymers and to articles prepared therefrom.
Polysaccharides are inexpensive and have good mechanical properties, but cannot be easily processed as thermoplastics. To take advantage of their low cost, attempts have been made to blend them with synthetic polymers, such as polyolefins, to produce more useful materials. However, the resulting materials often suffer from several problems. For example, the physical properties of the blend of the polysaccharide starch with polyolefin are adversely affected by the incompatibility of and poor adhesion between the polar starch and the non-polar polyolefin. In order to solve this problem, the starch must be modified, or compatibilized with the polyolefin, thereby increasing the cost of the blend. When more polar thermoplastics are employed in the preparation of the blend, other physical properties such as moisture resistance can be adversely affected. It would be desirable to provide a composition having useful mechanical properties comprising a polysaccharide and another hydroxy-functional polymer which is compatible therewith.
The present invention is a composition comprising (1) a polysaccharide, a modified polysaccharide or a naturally-occurring fiber or particulate filler and (2) a thermoplastic hydroxy-functional polyether derived from monomers containing 1 or more epoxy groups.
The hydroxy-functional polyether has been found to adhere strongly to a polysaccharide. This adhesion, and the generally good physical properties of hydroxy-functional polyethers, allows for the preparation of hitherto unknown materials with useful physical properties.
The compositions of the present invention are suitable for use in fabricating molded, extruded or foamed articles, containers, films, film laminates, or coatings using conventional fabricating techniques such as extrusion, compression molding, injection molding, blow molding and similar fabrication techniques commonly used to produce such articles. Examples of such articles include films, foams, sheets, pipes, rods, bags, boxes, meat trays, egg cartons, cups and plates, cutlery, and other disposable consumer items. The compositions of the present invention are also suitable for use as adhesives and encapsulating agents.